Steering not right

[vette]

That'll be 5c please

Hmmm, gettin a little expensive. Used to be 2 pence. :highly_amused:

 

[red57]

Very interesting subject and discussion.
As others have pointed out the issue can be summarized to "The problem is the relationship of the arm on the rocker shaft to the position of the left road wheel" so lets discuss just that aspect.

I'm a little concerned that you may not be giving enough credence to your having adjusted the camber to -1/2° from the standard +1° .
If this has been achieved by moving the top of the king pin in, as opposed to moving the bottom out, that will, in of itself, change the relationship of the rocker shaft to the position of the left road wheel.
( It will make the left wheel turn out)
To correct this you will need to turn the steering wheel to the right to make the left wheel point straight ahead.
Turning the wheel to the right to make the wheel point straight ahead will move the peg off the "high point" of the worm.
Obviously you can still get the "toe" correct by shortening the center rod BUT the peg NOT BE be on the high point of the worm.
Although it is indeed possible that the replacement rocker shaft is incorrectly made for experimentation, I would be inclined to return the camber of the left wheel to +1° before doing anything else.
That'll be 5c please

Nice succinct summary. I've run 1/2* negative for over 25 years so I just think of it as 'normal'. However, you made me stop and think about it and that's good because this time around there is a difference I wasn't considering. I always used urethane eccentric bushings in the lower control arms (so the lowers moved out some) in conjunction with eccentrics in the upper knuckle (so the uppers moved in some) and the combined effect made very little if any change. But this time around I installed adjustable plates under the shocks and concentric urethane lower control arm bushings (so the lowers didn't move, therefore all movement is inward at the top now). In the past the tightest spot in the box was about 1/2" on the steering wheel to the right of center, which I can live with just fine but the 4 o'clock position is more than I can accept. So, I appreciate you triggering the review and I will try returning to +1* on the drivers side to see what that does.

My last experiment above also showed the different rocker shafts are having an affect too. The old rocker shaft brought things back quite aways from where the new shaft had things and I think the twist in the old one from the wreck is at about 3-4* (each spline is 10* and the twist looks visually like somewhere between 1/4 and 1/2 a spline - unfortunately, I have no good way to measure the twist) so, returning to +1* combined with whatever the amount of twist is in the old shaft may add up to solving the problem.

Ironically, instead of working on it today, I spent quite a while searching for info on converting to rack & pinion simply because I'm done racing (SOVREN wouldn't allow that king of mod when I was racing) and now I want the best driving car possible. For over 30 years, my best friend and I traveled all over the Northwest in our sports cars. He drove a '54 MGTF with a Volvo B18 so we were pretty well matched and often, on longer tours, we would swap cars. The TF with an MGA rack & pinion was waaaaaay nicer/easier to drive than my Healey - no wandering, no constant corrections, went steady wherever you pointed it. So, this morning I started daydreaming about how nice it would be to not have a wanderer. Then I read your write up on the acmefluid site and it sounds like it's a challenge. From racing I'm familiar with Ackerman and bump steer principles but I have never actually tried to get that deep into chassis set-up. So, after todays research, I'm now back to thinking I should focus on solving the problems I already have instead of creating new problems.

Anyway, I appreciate the input. I will report back when I have some new info.
Thanks,
Dave

 

[Bob_Spidell]

...
I'm a little concerned that you may not be giving enough credence to your having adjusted the camber to -1/2° from the standard +1° .
If this has been achieved by moving the top of the king pin in, as opposed to moving the bottom out, that will, in of itself, change the relationship of the rocker shaft to the position of the left road wheel.
( It will make the left wheel turn out) ...

I understand this intuitively, but can't picture in my head why this is so, can you elaborate por favor?

 

[AHS3903]

Hmmm, gettin a little expensive. Used to be 2 pence. :highly_amused:

Inflation ... what can I say. Gotta eat you know :highly_amused::highly_amused:

 

[AHS3903]

Hi Bob, "Elaboration".
Consider this situation; you have decided that you want to decrease the camber of the left (drivers side) wheel by 2°. (Maybe you want to play roundy roundies).
You have set the steering to straight ahead and somehow locked it in that position.
Now, to produce the negative camber i.e. change the camber from the original +1° (wheel out at the top) to -1° you need to move the top of the king pin inward. (You could move the bottom out but we are ignoring that for the present).
This can be done various ways with an adjustable shock mounting plate, bending the shock arms, or eccentric bushes in the upper trunnion.
You use one or a combination of these methods to move the top of the king pin inward.
When that movement happens, because the ball joint on the end of the steering side rod is in a fixed position (locked steering remember) the swivel axle has to rotate slightly on the king pin.
That movement appears as "toe out".
In this case, having changed the camber on only 1 wheel only the 1 side will actually be toed out.
To correct the excessive toe out, because there is no adjustment available between the steering box and the left wheel (fixed length side rod), it would be necessary to shorten the center rod. (To do this in practice you would have to unlock the steering make the toe adjustment)
After readjusting the toe and returning the steering wheel to the original position in which you had previously locked it the car would be tracking left.
It would be necessary to turn the steering wheel to the right to make the car track straight.
Turning the steering wheel to the right would move the peg away from the high spot on the worm.

 

[glemon]

There is a lot more expertise than I have on this forum and topic, but I will add a few things that may be somewhat relevant.

First, when I have a problem on a car after I fixed something, I go over the list in my head of what I have touched (also in your case the accident) between the time it worked right and the time it worked wrong. And the problem is almost always found somewhere within those parameters. You just identified camber plates, anything else? Did you take apart the front suspension when doing repairs? Seems to be an issue present even when you replace the primary suspects from the steering box area with other parts.

Certainly appears from the description to be the result of a part made wrong or turned cattywhompus or bent and not small suspension adjustment issue.

Second, on rack and pinion conversion. Never driven a Healey with it, have driven couple TR3s, Is the steering lighter and tighter?, yes, Does it still feel like you are still driving a TR3?, no, not to me anyway.

 

[red57]

First, when I have a problem on a car after I fixed something, I go over the list in my head of what I have touched (also in your case the accident) between the time it worked right and the time it worked wrong. And the problem is almost always found somewhere within those parameters. I agree, the problem in this case is that everything was touched.

You just identified camber plates, anything else? Did you take apart the front suspension when doing repairs? Yes, this car was on a rotisserie for over 6 years of metal work and there was not a bolt/nut left on it - entire steering box, rod ends, all bushings, new kingpins, wheel bearings, seals, etc. replaced/rebuilt. Literally everything that could come apart was apart.

Seems to be an issue present even when you replace the primary suspects from the steering box area with other parts.

Certainly appears from the description to be the result of a part made wrong or turned cattywhompus or bent and not small suspension adjustment issue. Turns out you are right & I'll will post the details next.

Second, on rack and pinion conversion. Never driven a Healey with it, have driven couple TR3s, Is the steering lighter and tighter?, yes, Does it still feel like you are still driving a TR3?, no, not to me anyway. I pretty much talked myself out of that yesterday .

Thanks, I think we have the same approach to problem solving.
Dave

 

[red57]

Yaaaay, I am a happy camper again. I found the problem and everything seems to be right with the world again. I can't thank all of you who offered input enough because that's how I finally zeroed in on the problem.

I started today by following Mike's suggestion to put the driver's side back to +1* camber and it did change things, but unfortunately, not enough to solve the problem so I went back to the idea that the replacement shaft was the culprit.

In one of the first posts of this thread I showed a picture of the new rocker shaft splines, this was about the 'keys' to orient the shaft, every 90* where one spline is ground out of the shaft to match the spot in the arm where there is a wide spot with no spline. The removal of the splines from the shaft was done very sloppily and at a slight angle to the shaft. Such that they removed all of one spline at the end of the shaft, but as they went up the shaft they wandered over and removed part of the adjacent spline. Here are several pictures to try to show what I'm talking about.


So, since there are 36 splines which equals 10* per spline. My measuring with a protractor suggested the arms were about 10* off when the box was centered. So all that, coupled with the sloppy way they seemed to have ground out part of one spline and part of the adjacent one, I decided to grind away the partial spline to re-align the arm by one tooth. I will have to be careful in the future because it's now possible to put the arm on one tooth off from where it is now.


So, I put it together and my theory worked! The steering box is centered straight ahead, the arms are equal angles and the hubs are pointed straight - everything seems pretty symmetrical.



Now, obviously there will be some fine tuning when I have the motor in and the suspension is on the ground and fully loaded but I think that will all be within normal adjustment ranges.

Again, thank you all for the help and allowing me to dump this mess in public.
Dave

 

[steveg]

Dave,
This was a wonderful exercise in problem-solving! Thank you for seeing it through with all the followups with pictures!

Glemon brings up a basic lesson in troubleshooting:
"Something's either broken or it's changed"

 

[glemon]

That was fun, from the bleacher seats anyway. When I have a problem like that, I go over in my mind over and over again, somewhere along the spectrum of enjoyable mental exercise and manic obsession.

Glad you got it solved.

 

[Bob_Spidell]

Thanks, Michael. I get why moving the top of the king pin out--with eccentric bushings, shock plate, etc.--changes toe, but does moving the bottom of the king pin out do something different? It seems to me the results would be the same.

Edit: Asking pesky questions because I want to put aftermarket shock plates under the stock mounting plates so I can go from 1-1.5deg pos. to 0deg (probably should put the DWM steering column in first to see what it improves). Do you think that'll require shortening the cross link?

 

[DerekJ]

Who was responsible for the sloppy spline work? After my crash my splines were completely twisted so I bought a replacement shaft from DWR.

 

[vette]

As has been said earlier, thanks for seeing it thru with all of us. It certainly brings valuable experience to us all and I know it was tedious for you to keep sharing all the detail. I congratulate you on your demeanor in getting back to each and every one of us. Thanks again and happy that you got a solution. Hopefully you'll never have to take it off again but I'm sure you'll quickly notice if you get it off a tooth.
PS: it's a shame that's the type of manufacture we are forced to buy.

 

[steveg]

Thanks, Michael. I get why moving the top of the king pin out--with eccentric bushings, shock plate, etc.--changes toe, but does moving the bottom of the king pin out do something different? It seems to me the results would be the same.

Edit: Asking pesky questions because I want to put aftermarket shock plates under the stock mounting plates so I can go from 1-1.5deg pos. to 0deg (probably should put the DWM steering column in first to see what it improves). Do you think that'll require shortening the cross link?

Bob,
Would think you could get your camber change with the offset bushings, especially if you used them on the bottom, too. Adjustable plates seem like overkill pricewise.

Moving the bottom pins outward would entail some kind of adjustment where the flange notches interface with the square pins on the chassis mounts.

Several of my friends have the DW steering boxes - they drop right in.

 

[Jack T]

An excellent example of why good used parts can be a better choice than repops.

 

[red57]

Who was responsible for the sloppy spline work? After my crash my splines were completely twisted so I bought a replacement shaft from DWR.

This one came from SCparts - can't find the receipt but it came with an orange plastic web/net protector shield on it with their label and part numbers that I still have.

I wish I had known DWR had them when I bought it but they don't show on their website with all the other steering box parts and I didn't think to call them.

I had no luck finding a good used one and this was the only new one I could find at the time, so I bought it. I didn't really like the looks of it when I got it but I didn't think I had any choice. This was several years ago and they may well have improved or found another manufacturer by now.

I noticed that now there are at least 3-4 of the 'usual suspects' selling them but I don't know if they have different sources or if one shop is making them all.

Dave

 

[Bob_Spidell]

Steve,

I already bought the plates, at a slight discount, from someone on the email list. I have eccentric bushes in the top trunnion already; they didn't change the camber a whole lot. For some reason, my BJ8 had excessive pos. camber from the day I bought it; the driver side front bottom A-arm bracket was bent from (probably) hitting a curb or parking stop, but both sides were equally 'bow-legged,' and my front tires wear excessively on the outer edge of the tread (but it tracks true).

I finally figured out the problem with my MIG welder, and my skills are to the point I could trust my welds on suspension, plus I could both elongate and widen the holes so that I could fiddle with the caster angle as well if necessary. I haven't had a lot of luck with alignment shops--Healeys are an unknown species to most of them--and I plan on buying what looks to be a credible DIY system (anyone have experience with this?):

https://www.wheelalignmenttools.com/product/4-wheel-alignment-system/

 

[Bob McElwee]

Dave, I too have enjoyed this from the bleacher seats and I'm glad the problem has finally been solved.
I remember meeting you at Road America during the USA/England Challenge races. We saw your car and trailer and were really impressed that you drove to the races and then 'converted' the road car into a race car.
Good luck with the rest of your project, may the rest go smoothly.

 

[AHS3903]

Well there really 2 ways to overcome the problem of steering box center position if you want to produce negative camber.
One is to move the bottom of the kingpin out AND move the top in in roughly equal amounts.
The other is to make up an adjustable length side rod for the drivers side which will allow the relationship between the hub and the steering position to be set up before adjusting the toe in.
Incidentally with negative camber induced solely by moving the top of the king pin in usually the center rod will be too long unless the side rods are shortened.
BTW all of this screws up bump steer royally.

 

[Bob_Spidell]

BTW all of this screws up bump steer royally.

I'm hoping to achieve 0deg camber and whatever-the-book-says--I think it's 1deg pos.--caster will that make bump steer worse?

I've looked into adjustable side tie rods; supposedly, Kilmartin makes them but they're not listed and no one replies to my emails. If necessary, I'll pull out my 'Aussie-to-American' dictionary and give them a call .